In the construction of aircraft and other vehicles having combustion engines and fuel tanks, it is desirable to reduce the presence of electrical conductors in the environment of the fuel tank to reduce the potential of an electrical spark in the area of the fuel tank. Non-conductive plastic nut and bolt fastener assemblies have been used in these environments in place of conductive metal nut and bolt fastener assemblies. Additionally, replacing thousands of metal fastener assemblies used in constructing an aircraft or other vehicle with plastic fastener assemblies reduces the weight of the aircraft or vehicle, making the aircraft or vehicle more fuel efficient. However, existing plastic fastener assemblies are known to lose preload torque. A plastic fastener assembly comprising a threaded bolt and nut can lose preload torque or have the fastener assembly preload torque decrease due to the unthreading of the nut from the bolt over time.